##非常简单的一个redis实现
###Supported Commands
####String
append bitcount decr get getbit getrange incr incrby mget msetnx set setbit setrange strlen
####keys del exists randomkey rename keys type
####list blpop lrange brpop lrem brpoplpush lset lindex ltrim linsert rpop llen rpoplpush lpop rpush lpush rpushx lpushx